Rule of 40: Calculator, Formula, and 2025 Benchmarks for SaaS

The Rule of 40 is a SaaS benchmark stating that a healthy software company's annual ARR growth rate plus its profit margin should equal at least 40%. The formula is YoY ARR Growth % + Profit Margin %, where "profit margin" is typically either EBITDA margin or Free Cash Flow margin depending on the investor asking. The 2025 private SaaS median is approximately 28% per Bessemer State of the Cloud 2025 — meaning the median company misses the Rule of 40 by 12 points. Top-quartile companies score 48% or higher. The metric exists to force a trade-off: a company can grow slowly and be profitable, or grow fast and lose money, but the sum of those two must stay above 40% to qualify as a high-quality SaaS business.

What the Rule of 40 actually is

The Rule of 40 is a heuristic for evaluating SaaS companies on a single number that balances growth and profitability. The premise: fast-growing companies are often unprofitable, slow-growing companies should be profitable, and companies that are both slow and unprofitable are not investable. The rule forces every SaaS company into one of three categories: (1) growth-at-any-cost, where the growth rate more than compensates for the losses, (2) profitable-and-slow, where profitability makes up for modest growth, or (3) hybrid, where moderate growth and modest profit both contribute.

The math is intentionally simple. Add the annual growth rate to the profit margin. If the sum is 40 or above, the business is a healthy SaaS company. Below 40, something needs to change.

The rule was popularized by Brad Feld and Techstars investors in the mid-2010s and has since become the default framing for SaaS efficiency, replacing older heuristics like "growth over 50% is enough." The 40% threshold is not magic — it's a convention. But conventions become standards when enough investors use them, and the Rule of 40 is now the primary single-number SaaS benchmark across both private and public markets.

The formula, with every variable defined

The formula is:

Rule of 40 = YoY ARR Growth % + Profit Margin %

Both variables need specific definitions to be useful.

YoY ARR Growth % is the trailing twelve months of ARR growth as a percentage. If ARR at the start of the year was $10M and it's $15M at the end, growth is 50%. It should not be calculated from revenue (GAAP revenue includes services and setup fees); it should be calculated from recurring revenue only.

Formula:

YoY ARR Growth % = (Current ARR - ARR 12 months ago) / ARR 12 months ago × 100

Profit Margin % is where the two standard definitions diverge:

• EBITDA Margin = EBITDA / Revenue × 100. Older Rule of 40 formulations use EBITDA. More forgiving because it excludes interest, taxes, and depreciation/amortization.
• FCF Margin = Free Cash Flow / Revenue × 100. Newer investor standard. Free Cash Flow = operating cash flow minus capex. Harder to hit because it reflects actual cash generation.

The two can produce meaningfully different scores. A company at 35% ARR growth with 10% EBITDA margin (Rule of 40 = 45%) might be at 35% ARR growth with 0% FCF margin (Rule of 40 = 35%) because of working capital movement and capex. The gap matters: serious investors in 2025 default to the FCF version.

A third variant, used mostly in public markets, substitutes GAAP operating income margin. This is the most stringent definition and typically produces the lowest score. Most SaaS boards use the EBITDA version internally and report the FCF version to investors.

The 2025 benchmarks

The 2025 private SaaS benchmarks, drawn from Bessemer State of the Cloud 2025, SaaS Capital 2025, and OpenView Benchmarks 2025:

Stage-specific patterns:

• Seed/Series A companies: growth is usually 60%+ but FCF margin is -40% to -80%. Rule of 40 often lands at -20% to +20% at this stage. The rule is not particularly useful at Seed because profitability isn't the goal.
• Series B companies: growth typically 50-80%, FCF margin -20% to -40%. Rule of 40 often 10-40%. Getting above 40% is the stretch goal.
• Series C and later: growth 30-50%, FCF margin approaching zero or positive. Rule of 40 frequently above 40%. This is where the metric becomes definitive.
• Public SaaS: growth 15-40%, FCF margin 5-25%. Rule of 40 is the primary comparison metric.

A useful pattern: the median Rule of 40 has been compressing each year from 2021 (around 40%) to 2025 (around 28%). This reflects both slower growth rates across the SaaS industry and the broader market discipline around profitability. The top quartile has held more stable around 48-55%.

Worked examples by stage

Three hypothetical companies to illustrate how the Rule of 40 plays out at different stages:

Seed-stage company. $2M ARR → $5M ARR (150% growth). FCF margin -100% (they burned $5M to make $5M). Rule of 40 = 150 - 100 = 50%. Excellent by the rule, which is why pure growth is acceptable at Seed.

Series B company. $20M ARR → $35M ARR (75% growth). FCF margin -25% (burned $8.75M against $35M revenue). Rule of 40 = 75 - 25 = 50%. Top-quartile performance. Would justify a strong Series C.

Mature SaaS. $200M ARR → $240M ARR (20% growth). FCF margin 15% (generating $36M in free cash flow). Rule of 40 = 20 + 15 = 35%. Below the rule. The company is growing modestly and making money but isn't exceptional at either. Common late-stage SaaS profile.

Struggling SaaS. $50M ARR → $55M ARR (10% growth). FCF margin -5% (still burning modestly). Rule of 40 = 10 - 5 = 5%. Well below the rule. Needs either accelerated growth or a path to profitability; probably both.

How to use the Rule of 40 in practice

The Rule of 40 is most useful in three specific contexts.

Board reporting and investor updates. Include the current Rule of 40 (trailing 12 months) and the trajectory over the last 4-8 quarters. Investors track trajectory more than level. A Rule of 40 moving from 20% to 35% over four quarters tells a better story than a stable 45%.

Competitive benchmarking. Compare the company's Rule of 40 to the specific peer set the board uses. "We're at 38% against a peer median of 28%" is actionable. A raw number without a comparison is noise.

Strategic trade-off decisions. When considering whether to accelerate hiring (reduces profit margin, accelerates growth) or slow it (increases margin, slows growth), the Rule of 40 is the single number that captures whether the trade is favorable. Run the scenarios, look at the forward Rule of 40, and pick the path that improves it.

Where the Rule of 40 is less useful:

• Pre-revenue or sub-$1M ARR companies. The growth rate is volatile (small denominators) and profitability is irrelevant.
• Companies in transition (pricing model changes, major customer migrations, acquisitions). Non-recurring events distort the calculation.
• Very mature SaaS (>$500M ARR). Public market comparisons are cleaner; private benchmarks get thin.

Common mistakes in Rule of 40 calculation

Using GAAP revenue instead of ARR. GAAP revenue includes services, setup fees, and other one-time items. ARR is purely recurring. A company with a meaningful services business will show higher "revenue growth" than "ARR growth" — use ARR to avoid inflating the score.

Using EBITDA when the investor asked for FCF. Know which version the audience expects. Defaulting to EBITDA in a Series C pitch will be caught. Defaulting to FCF in a Seed discussion makes the company look worse than peers.

Reporting a single quarter's score. Quarterly scores are noisy. The standard is trailing twelve months (TTM) for both growth and margin. Report the 4-quarter trend, not a point-in-time snapshot.

Ignoring gross margin. The Rule of 40 doesn't explicitly include gross margin, but a low-gross-margin business (below 70%) struggles to score well even with good growth and opex discipline. A company with 55% gross margin will never achieve a 40+ Rule of 40 at scale.

Comparing across business models. Infrastructure SaaS, vertical SaaS, and consumer SaaS have different growth-to-margin profiles. A 40% score means different things in each. Compare within category, not across.

Rule of 40 versus Burn Multiple: how they relate

Both metrics measure SaaS efficiency, but from different angles.

Rule of 40 is margin-plus-growth. It works at any stage but is most informative when the company is within reach of profitability.

Burn Multiple is cash efficiency per dollar of new ARR. It works best at pre-profit stages where the company is still burning.

The two correlate — a company with a great Burn Multiple generally has a great Rule of 40 too — but they don't always move together. A company could have a healthy Burn Multiple (1.0x, indicating efficient growth) with a poor Rule of 40 if the absolute growth rate and margin are both modest. Or vice versa.

Use both in the same dashboard. Burn Multiple answers "are we spending efficiently?" Rule of 40 answers "are we balanced between growth and profit?"

Key takeaways

The Rule of 40 is the single most useful SaaS benchmark for evaluating the trade-off between growth and profitability. The formula is simple, the 40% threshold is a convention with real weight in the market, and the 2025 median of 28% means most private SaaS is below the rule. Top-quartile companies score 48%+. The metric becomes critical at Series B and beyond, when growth rates compress and profitability becomes a lever that matters. Use the FCF version for external communication in 2025; use it alongside Burn Multiple for early-stage companies.

For a template that calculates the Rule of 40 alongside 19 other SaaS KPIs with 2025 benchmark scoring, see the Meritra SaaS Financial Model. For the companion efficiency metric, see Burn Multiple Explained. For the dashboard that surfaces both: CFO Dashboard Template.